Try putting some hot water in a "cup" you make from paper and you may find that the thin plastic barrier makes some functional sense. I agree however, that I'd

Try putting some hot water in a "cup" you make from paper and you may find that the thin plastic barrier makes some functional sense. I agree however, that I'd rather just use re-usable glass or metal cup (with a handle or suitable insulated wrappping) and avoid the potential for hot liquids leaching things out of plastic!